<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
       p{
        color: green;
       }
       #nihao{
        color:yellow;
       }
       .text{
        color: blue;
       }
    </style>
</head>
<body>
    <p  class="text">哈哈</p>
</body>
</html>